The mosque (sometimes called ‘Bekçi Camii’/Mosque of the Caretaker) dates from the reign of sultan Çelebi Mehmet I (1413-1421). It was built, in the name of Ibni Bezzaz, by Hafizüddin Efendi. Ibni Bezzaz(i) Kerderi was a major scholar of the Hanefi school of law, who was born in Khwarezm (Central Asia) and came to Anatolia; he died in Bursa in 1424.
The square prayer hall (7,89 x 7,94 m) is covered by a dome, and is preceded by a porch/vestibule (7,89 x 3,40 m) on its north side. The building was severely damaged by the 1855 Bursa earthquake; its present state is the result of a thorough restoration in 1979.

Correspondent: J.M.Criel, Antwerpen.
Sources: ‘Vakıf Abideler ve eski Eserler (volume III)’ - Vakıflar Genel Müdürlüğü, Ankara 1983 , Wikipedia
& Website of ‘liveinbursa.com’.